ML19312B937

Proposed Tech Spec 3.6 Allowing Maint Intervals on Hatches & Isolation Valves for Short Periods of Time

ML19312B937
Person / Time
Site:	Oconee
Issue date:	09/04/1974
From:	DUKE POWER CO.
To:
Shared Package
ML19312B933	List: ML19312B932 ML19312B937
References
NUDOCS 7911270725
Download: ML19312B937 (2)

Text

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3.6 REACTOR BUILDING Applicability Applies co the containment when the reactor is subcritical by less than 1% Ak/k.

Objective To assure containment integrity during startup and operation.

Specification 3.6.1 Containment integrity shall be maintained whenever all three (3) of the following conditions exist:

a. Reactor coolant pressure is 300 psig or greater

b. Reactor coolant temperature is 2000 F or greater

c. Nuclear fuel is in the core 3.6.2 Containment integrity shall be maintained when the reactor coolant system is open to the containment atmosphere and the requirements for a refueling shutdown are not met.

3.6.3 The containment integrity shall be intact whenever positive reactivity insertions which would result in the reactor being suberitical by less than 1% Ak/k are made by control rod motion or boron dilution.

3.6.4 Exceptions to 3.6.1, 3.6.2, and 3.6.3 shall be as follows:

a. If either the personnel or emergency hatches become inoperable, except as a result of an inoperable door gasket, the hatch shall be restored to an operable status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, or tha reactor shall be in cold shutdown within the next 36 houra.

If a hatch is inoperabic due to an inoperable door gasket:

1. The remaining dear of the affected hatch shall be closed and sealed.

2. The hatch shall be restored to operable status within seven days or the reactor shall be in cold shutdown within the next 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

b. A containment isolation valve may be inoperable provided either:

1. The inoperable valve is restored to operable status within four hours.

2. The affected penetration is isolated within four hours by the use of a deactivated automatic valve secured and locked in the isolated position.

3.6-7911270 7Y

3. The affected penetration is isolated within four hours by the use of a closed manual valve or blind flange.

4. The reactor is in the hot shutdown condition within 12 hcurs and cold shutdown within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

3.6.5 The reactor building internal pressure shall not exceed 1.5 psig or five inches of Hg if the reactor is critical.

3.6.6 Prior to criticality following refueling shutdown, a check shall be made to confirm that all manual containment isolation valves which should be closed are closed and tagged.

Bases The Reactor Coolant System conditions of cold shutdown assure that no steam will be formed and hence no pressure buildup in the containment if the Reactor Coolant System ruptures.

The selected shutdown conditions are based on the type of activities that are being carried out and will preclude criticality in any occurrence.

The reactor building is designed fer an internal pressure of 59 psig and an external pressure 3.0 psi greater than the internal pressure. The design external pressure of 3.0 psi corresponds to a margin of 0.5 psi above the differential pressure that could be developed if the building is sealed with an internal temperature of 1200F with a barometric pressure of 29.0 inches of Hg and the building is subsequently cooled to an internal temperature of 800F with a concurrent rise in barometric pressure to 31.0 inches of Hg. The weather conditions assumed here are conservative since an evaluation of National Weather Service records for this area indicates that from 1918 to 1970 the lowest barometric pressure recorded is 29.05 inches of Hg and the highest if 30.85 inches of Hg.

Operation with a personnel or emergency hatch inoperable does not impair containment integrity since either door meets the design specifications for structural integrity and leak rate. The time lLnits imposed permit completion of maintenance action and the performance of a local leak rate test when required or the orderly shutdown and cooldown of the reactor.

Timely corrective actica for an inoperable containment isolation valve is a' specified.

When containment integrity is established, the limits of 10CFR100 will not be exceeded should the maximum hypothetical accident occur.

REFERENCES FSAR, Section 5 3.6-2

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